$56.8 \times 7.1 = $
Explanation: ${5}$ ${6}$ ${8}$ ${7}$ ${1}$ ${\times\vphantom{0}}$ ${.}$ ${.}$ ${0.8}\times {0.1}= {0.08}$ ${8}$ ${6}\times {0.1}= {0.6}$ ${6}$ ${50}\times {0.1}= {5}$ ${5}$ ${0.8}\times {7}= {5.6}$ ${6}$ ${0}$ ${6}\times {7}+C{5}= {47}$ ${7}$ ${50}\times {7}+C{40}= {390}$ ${9}$ ${3}$ ${+\vphantom{0}}$ ${4}$ ${0}$ ${3}$ ${2}$ ${8}$ ${+\vphantom{0}}$ ${4}$ ${0}$ ${3}$ ${2}$ ${8}$ ${.}$ The top number has $1$ digit to the right of the decimal. The bottom number has $1$ digit to the right of the decimal. The product has $1+1=2$ digits to the right of the decimal. $56.8 \times 7.1 = 403.28$